ABSTRACT Physical, economic, and socioeconomic environmental factors in one's neighborhood have been shown to influence substance use and substance use disorder, but the literature specific to the ecological correlates of marijuana is surprisingly limited and simplistic. With medical marijuana legalized in 23 states and Washington D.C. in the past two decades and recreational marijuana legalized in Colorado, Washington, Alaska, Oregon, and Washington D.C. recently, marijuana-related environments in the U.S. have changed dramatically. To appreciate the impacts of these laws, empirical data on the relationship between environment and marijuana-related outcomes are much needed. The goal of this project is to test a series of hypotheses on the relationships of multiscale environmental factors to marijuana use, marijuana use disorder, purchase behaviors, and other related outcomes, with an emphasis on policy-relevant modifiable factors in neighborhood environments. This empirical research aims to provide evidence-based guidance to community public health and urban planning policymakers regarding marijuana regulation strategies, such as licensing policies, zoning ordinances, tax and pricing, and policies to limit types of products sold, that may ameliorate negative health and socioeconomic consequences related to marijuana. Specifically, we propose: 1) Aim 1 (physical environment): to quantify the relationships of availability and proximity of marijuana stores to marijuana use, marijuana use disorder, and purchase behaviors; 2) Aim 2 (economic environment): to quantify the relationships of marijuana price and product variety to marijuana use, marijuana use disorder, and purchase behaviors; and 3) Aim 3 (socioeconomic environment): to examine whether and how neighborhood SES influences the relationships of physical and economic environments to marijuana use, marijuana use disorder, and purchase behaviors. We will leverage innovative sources of objectively measured environmental data and an original online survey on a representative sample of 18,000 adults aged 18 or older in 20 continental states with marijuana legalization. This project is innovative in its focus on neighborhood-level multiscale environmental factors potentially modifiable by policies and the use of unprecedented sources for objectively measured environmental data. Further strengths include the application of a comprehensive ecological framework, an original survey on large state-representative samples with extraordinarily rich information on marijuana-related outcomes, measures to distinguish recreational use from medical use, collection of data on both objective and perceived environmental factors, and a trans-disciplinary team with demonstrated relevant expertise.